Photonic nanostructures can be used for many applications besides solar cells--for example, optical sensors for cancer markers or other biomolecules. A team at HZB using computer simulations and machine learning has now shown that the design of such nanostructures can be selectively optimised. The results are published in Communications Physics. Nanostructures can increase the sensitivity of optical sensors enormously--provided that the geometry meets certain conditions and matches the wavelength of the incident light. This is because the electromagnetic field of light can be greatly amplified or reduced by the local nanostructure.